Banca de DEFESA: FRANCINE BRANCO TAKAMOTO

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : FRANCINE BRANCO TAKAMOTO
DATE: 25/02/2025
TIME: 13:30
LOCAL: Campus Feliz (defesa online) - link: meet.google.com/uqb-mkkr-uux
TITLE:

Evaluation of the Impact of Limonene Dioxide Incorporation in DGEBA Epoxy Resin: Effect on Thermal, Rheological, Mechanical, and Dynamic Mechanical Properties

KEY WORDS:

Limonene Dioxide. DGEBA Epoxy Resin. Bioepoxy. Glass Transition Temperature. Viscosity.

PAGES: 80
BIG AREA: Engenharias
AREA: Engenharia de Materiais e Metalúrgica
SUBÁREA: Materiais Não-Metálicos
SPECIALTY: Polímeros, Aplicações
SUMMARY:

This study investigated the impact of incorporating different contents of limonene dioxide (LDO) into epoxy resins based on diglycidyl ether of bisphenol A (DGEBA) on thermal, rheological, mechanical, and dynamic mechanical properties. Six compositions were studied, named according to the mass ratio of DGEBA epoxy resin and LDO: R100L0 (100% epoxy resin), R80L20 (80% epoxy resin and 20% LDO), R60L40 (60% epoxy resin and 40% LDO), R40L60 (40% epoxy resin and 60% LDO), R20L80 (20% epoxy resin and 80% LDO), and R0L100 (100% LDO). A 1:1 ratio of resin/LDO and hardener was used. In the first stage of the study, the curing conditions proposed by the supplier were analyzed. In a second stage, a post-curing condition was included, and the samples were characterized by DSC, TGA, DMA, Sonelastic, Shore D hardness, gel content, viscosity, and gel time. The results indicated that partial or total replacement of DGEBA with LDO resulted in changes in the studied properties. The glass transition temperature (Tg) obtained via DSC showed a progressive reduction, ranging from 106.4 °C in the R100L0 sample to 85.5 °C in the R0L100 sample. The gel time was inversely proportional to the LDO content, indicating that higher concentrations of LDO reduce the crosslinking density and accelerate the curing process. Samples with high LDO contents exhibited lower thermal stability, as evidenced by TGA analysis. The R40L60 formulation stood out for its balance between thermal, rheological, and mechanical properties, presenting a shorter gel time (9.65 minutes), suggesting good reactivity and compatibility between the components. It is concluded that LDO is a promising substitute in epoxy resins for a variety of applications, depending on the properties of interest. Furthermore, due to the viscosity value presented in the R0L100 sample, approximately 70 mPa.s at 25 °C, it has the potential to be used as a reactive diluent in epoxy resin systems.

COMMITTEE MEMBERS:
Presidente - DAIANE ROMANZINI
Interna - EVELINE BISCHOFF
Interno - EDSON LUIZ FRANCISQUETTI
Externo à Instituição - RENATE MARIA RAMOS WELLEN - UFPB
Externo à Instituição - MAURÍCIO CARPE DIEM FERREIRA XAVIER